The present invention relates to vehicle seating and in particular to a light weight seat frame for a vehicle seat assembly.
Several models of motor vehicles, such as vans and other multi-purpose vehicles, are equipped with rear seat assemblies that are removably mounted to the vehicle. The removable mounting enables a vehicle owner to remove the seat assembly from the vehicle to increase the vehicle's cargo capacity when needed. The seat assembly can be reinstalled when needed for transporting passengers. With bench type vehicle seats in particular, the large size of the seat assembly results in a heavy seat. This makes removal and reinstallation of the seat assembly a difficult task for all but the strongest of persons. The seat assembly frame is largely responsible for the seat assembly weight.
Accordingly, it is desirable to provide a removable seat assembly having a light weight frame to ease the burden when removing and reinstalling the seat assembly.
The vehicle seat assembly of the present invention includes a frame that is primarily made of magnesium components instead of heavier steel components. Many of the frame components are made of magnesium extrusions having a variety of cross sectional shapes. To maximize the strength for a given weight of material used, many of the extruded parts have hollow cross sections.
While a hollow cross section provides a high strength to weight ratio, the relatively thin walls of the cross section do not offer sufficient material thickness for the attachment of threaded fasteners into the frame components. This is not a problem where a nut can be threaded onto a bolt to attach a component to the frame. However, with a component having a hollow cross section and a substantial length, there is no access to both sides of the frame wall needed for installation of a nut and bolt assembly. This is particularly true of the rear cross member of the seat cushion frame, to which several components are attached. Additionally, even when a nut and bolt assembly is used, the wall thickness of the hollow body may not provide sufficient strength. It is often necessary to spread the load of the nut and bolt assembly over a larger area to achieve the needed strength.
The seat frame of the present invention includes a rear cross member that is an elongated hollow body having two cavities sharing a common wall. To produce strong attachments of components to the rear cross member, tapping blocks are inserted into one of the cavities to the desired locations for the attachments. The tapping blocks consist of a larger solid body of magnesium having a bore therein for reception of a threaded fastener. The blocks provide sufficient material to form a threaded attachment. In addition, the tapping blocks have a large base plate that spreads the fastener load over a larger area.
The seat assembly rear cross member, by having a pair of cavities, enables two tapping blocks to be located at the same longitudinal position in the cross member, one in each of the cavities. This allows more components to be attached to the cross member at a single longitudinal location then if the cross member has only one cavity.
The seat cushion frame rear cross member also includes a forwardly extending flange at its lower edge. The flange has a notch forming a forwardly facing ledge that is used to facilitate mounting of the seat trim to the seat cushion frame. An elongated J-clip sewn to the edge of the trim has a tail end that is seated into the forward facing ledge. The ledge forms a pivot point for rotating the J-clip to align the J-clip opening with the extending flange. Tension in the seat cover then draws the J-clip onto the flange.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.